On tonight's episode of "The Flash," Barry went back in time to see if Dr. Harrison Wells/The Reverse Flash could teach him how to go fast enough to beat Zoom. Barry, haunted by being lied to again by someone close to him, was determined to not let Jay/Zoom torment Earth-2 and decided to run back to a time when Reverse Harrison Wells was still working with Barry at S.T.A.R. Labs. His plan was simple: knock out the past version of himself, pretend to be past Barry, get Reverse Wells to solve the speed force equation, and head back home to the present. Unfortunately Barry didn't account for Wells being able to discover who he really was, or that a wraith would follow him back in time to kill him. Barry learned some very valuable lessons this week, and may think twice about time traveling in the future. Cisco also continued to be plagued by vibes of Jay as Zoom, just like in last week's episode.

Tonight's episode kicked off with Barry (Grant Gustin) speed reading through as many text books and scientific journals as he could. After the revelation that Jay (Teddy Sears) was really Zoom, and that Barry still wasn't fast enough to beat him, Barry's entire goal was then to truly become the fastest man alive. Barry's emotional state in this episode was agitated, upset, focused, and determined. He reminded me a lot of Barry at the end of season one when he was obsessed with beating the Reverse Flash. Barry's adversaries always want him to get faster, and the more they hurt him, the greater his motivation to be faster becomes. It's really a double-edged sword, a trap, that Barry falls into, when he's pushed to the limits like this. After exhausting every textbook answer he could find, he decided to travel back in time to ask Reverse Flash Wells (Tom Cavanagh) how to crack the speed force code. Barry got the idea from Wally (Keiynan Lonsdale,) who was studying the works of car inventors who had passed away many years ago.

Barry's idea was shot down by Earth-2 Harry Wells because of the dangers of messing with the time stream. Caitlin (Danielle Panabaker) and Cisco (Carlos Valdes) were also apprehensive, but eventually agreed to help Barry. What's interesting about this episode is the time they decided to go back to. Caitlin, Cisco, and Barry dug back through all their case files and decided to send Barry back to a moment during season one, episode 11, in the episode "The Sound and the Fury." That's the episode where Hartley Rathaway (Andy Mientus) made his debut as the Pied Piper. Hartley was a former protege of Dr. Wells, and came back to hurt Wells after his ears blew out during the particle accelerator explosion. For Barry to go back to that episode and those moments, was an interesting choice, because no one on Team Flash knew about the Reverse Flash yet, Eddie was still alive, and Barry would have to incapacitate Hartley again.

Once Barry made it back to the Pied Piper timeline he was certain he could tranquilize past Barry and assume his life, much like he did to Earth-2 Barry in "Welcome to Earth-2." His plan had two hiccups that he didn't account for: a rogue time wraith and the intelligence of Reverse Flash Wells. It took absolutely no time at all for Reverse Flash Wells to figure out that this Barry was not his Barry. It was great to see Tom Cavanagh play the Reverse Flash Wells again, especially in the scene where he figured out Barry is lying. He tied Barry to his wheelchair and interrogated him about the future, about timelines, about Barry's intentions in this time, about failing his mission -- everything. Eventually Barry let him in on the plan, but only after straight up lying to Reverse Wells about finally getting his speed back and going home. It was so funny watching Cavanagh stand up with no problems when Barry was around, and then hop back into his wheelchair when Caitlin and Cisco were around. It must have been killing Barry not to tell his friends that Wells was lying to them, but he knew the timeline had to play out just as it had.

Barry's other problem in this episode, besides waiting on Wells to teach him about the speed force, was the time wraith -- a ghostly spirit that followed Barry through the timeline back with him. According to Reverse Wells, the job of a wraith is to correct the timeline, when someone "runs out of luck" or plays with it in a way that is out of bounds. The wraith chased Barry around Central City, essentially haunting him, threatening to kill him with its icy death grip. The only thing that could scare it away was Pied Piper's gauntlet vibrations, which came in handy when the wraith was let loose into S.T.A.R. Labs. At one point Cisco, Caitlin and Hartley were all hiding inside one of the prison cells, to protect themselves from the wraith. Barry also had to deal with himself in this episode -- past Barry -- which was a great metaphor for the inner struggle of a hero. When past Barry woke up and raced back to S.T.A.R. Labs, he was met by future Barry, and Wells and Barry had to come clean about what was really going on.

Cisco and Caitlin rolled with the time travel news, but they still weren't sure how to take down the wraith. They didn't have to wait long though, as Reverse Wells decided to give future Barry the codes to the tachyon enhancement. Before Barry went back to his own time he decided to do one last thing: he asked Eddie (guest star Rick Cosnett) to record a message for Iris (Candice Patton.) Iris was still missing Eddie, even a year after his death, and Barry knew that if Eddie could tell her how much he loved her and wanted her to be happy, that maybe she could move on. When Barry got back to his time and played Iris the message, she cried and smiled, knowing that Eddie would want her to be happy and to move forward. Eddie's presence in this episode was by far the most emotional element, as Rick Cosnett's joy and positivity reminded me what a bright character he was, and how dim Central City has been since his heroic death. It's possible he could return to the show, since he is alive on Earth-2, but that doesn't seem likely since Iris is starting to move on from him.

The episode ended with future Barry telling Cisco and Caitlin that they had one year to figure out how to defeat the wraith, and to be ready for him when he came back to his own time. Future Barry and past Barry worked together to outrun the wraith in the pipeline, and future Barry made it home. The wraith followed him through and almost killed him, but Pied Piper showed up with his gloves and sonic blasted it into oblivion. Apparently he's a friend of Team Flash now and even has a good relationship with his parents. Does that mean we'll see more of him on future episodes of "The Flash?" Hopefully, because Andy Mientus is always a delightful addition any episode. The final moments of the episode took Caitlin, Cisco and Barry into Reverse Wells' future room, and when Barry put the tachyon codes into Gideon, the speed force formula was revealed. Barry now has exactly what he needs to be fast enough to beat Zoom. We just have two wait two more weeks to find out how he'll do it. "The Flash" is on hiatus for the next two weeks, with the show returning for it's final six episodes on April 12.